Field of the Invention:
The invention in general relates to an arrangement for measuring a selected parameter of a liquid, and more particularly to apparatus which utilizes acoustic transducers.
Description of the Prior Art:
Acoustic methods are often utilized for determining a predetermined parameter of a liquid contained and movable within a structure. By way of example, the level of a liquid within a standing pipe or a vessel may be determined by a pulse echo arrangement wherein an acoustic transducer transmits a pulse through the liquid toward the liquid surface and the return signal therefrom, suitably processed, provides an indication of the liquid surface height above some reference point.
In another arrangement, diametrically opposed transducers coupled to the structure surface are arranged such that an acoustic pulse transmitted from one to the other will provide a different response when transmitted through a gas as opposed to through the liquid thereby giving an indication of the presence of the liquid, at the transducer level.
A problem often arises in the use of such systems in that acoustic energy transmitted through the fluid containing structure also propagates within the structure wall material and can severely degrade proper operation.
The present arrangement substantially reduces the wall-borne acoustic energy so as to provide for a more accurate detection system.